Patent Document 1 describes this type of air-conditioning hot-water supply system.
Patent Document 1 describes a heat pump system. In the heat pump system, a high-temperature cycle is formed by circularly connecting a high-temperature condenser, a high-temperature evaporator, a high-temperature compressor, and a high-temperature expansion valve; a first middle-temperature cycle is formed by circularly connecting a low-stage compressor, a first control valve, a four-way valve, an intermediate condenser/evaporator, a first expansion valve, and a heat-source-side heat exchanger; and a second middle-temperature cycle is formed by connecting to a suction side of the low-stage compressor through a second control value, intermediate condenser that can exchange heat with the high-temperature evaporator, a heat-source-side heat exchanger and the four-way valve, the second middle-temperature cycle being branched between a discharge side of the low-stage compressor and the first control valve. During the simultaneous operation of a high-temperature output and a low-temperature output, the absorbed heat from the intermediate condenser/evaporator can be used as the heat source for the high-temperature cycle, so that energy-saving operation can be performed. The second control valve is fully opened, and the opening degree of the first control valve is controlled in order that the discharge pressure of the low-stage compressor becomes a set value, whereby a stable operation is possible, even if the high-temperature output load and the low-temperature output load are not balanced.